MORPHOLOGICAL RELATIONSHIPS, GROWTH PATTERNS AND SOME ASPECTS OF REPRODUCTIVE BIOLOGY OF SIND DANIO Devario devario (HAMILTON 1822)

Abstract

This study described some morphological relationships, growth population factors and some biological aspects of Devario devario collected from the Atrai River of Dinajpur, Bangladesh from December 2016 to June 2017. Body size of 1300 individuals ranged from 4.6-8.1 cm and 1.12-6.94 g. The value of slope (b) were found as 2.523-3.248, 2.512-3.248 and 2.908-3.500 for female, male and combined sexes, respectively that were significantly different from the isometric point in March. Moreover, the values of “b” from length-weight relationship (LWRs) indicated isometric growth (b = 3) in the months of December, January, February, April and May for this fish. CFf ranged from 1.068±0.011 to 1.336±0.014, 1.027±0.011 to 1.207±0.012 and 1.054±0.007 to 1.247±0.006, for female, male and combined sexes, respectively while BWr varied from 99.699±1.063 to 106.071±0.995, 99.675±0.722 to 100.936±0.874 and 99.826±0.677 to 100.585±8.206 for female, male and combined sexes, respectively. In LLRs (among TL, SL, HL and FL), a strong relationship were found of TL vs. SL (r2 > 0.201), TL vs. FL (r2 > 0.012), FL vs. SL (r2 > 0.332), HL vs. TL (r2 > 0.001), HL vs. SL (r2 > 0.003) and HL vs FL (r2 > 0.049) among sexes of this species, respectively. The asymptotic lengths (L∞) were 7.5, 7.2 and 7.5 cm where growth rate (K) obtained as 0.78-1.8, 0.6-3.4 and 1.8-3.6 year-1 for female, male and combined sexes, respectively. Total mortality recorded as 1.22 to 3.06, 0.97 to 7.07 and 3.70 to 6.09 year-1; fishing mortality as -0.87 to -1.04, -0.97 to 1.09 and -0.05 to -0.23 year-1; natural mortality as 2.26 to 3.93, 1.94 to 5.98 and 3.93 to 6.14 year-1 for female, male and combined sexes, respectively. The highest probability of capture (L50) recorded at 5.74 to 6.10 cm 5.81 to 5.83 and 5.62 to 6.15 for female, male and combined sexes, respectively. The values of gonado-somatic index ranged from 32.75±1.82 (KS) to 44.12±2.73 (KS) with peak in May. The highest and lowest values of fecundity was estimate as 3253±289 (KS) and 4831±342 (KS). A significantly correction were found of fecundity (Fe) with TL (r2 > 0.012), BW (r2 > 0.006), GL (r2 > 0.058) and GW (r2 > 0.048), respectively. Lastly, the findings were firstly record on D. devario that would be the basis for future research and management.